Anaesthetic Management of A Case of Osteogenesis Imperfecta with Urinary Bladder Stone - A Case Report

Summary Sometimes in practice of anaesthesia, anaesthesiologist encounters patients with rare congenital diseases. To anaesthesiologist, these patients are a challenge due to inherent complications associated with the disease. Here, we are reporting a case of osteogenesis imperfecta who was posted for the surgery for vesical calculus. All investiga-tionswere doneto ruleout any cardio-respiratory abnormalities, bleeding disorders, which are commonly associated with these patients. Caudal epidural was chosen as anaesthesia technique of choice as spinal anaesthesia was anticipated to be difficult due to associated kyphoscoliosis. GA was avoided due to anticipated difficult airway, restrictive lung disease and susceptibility to malignant hyperthermia. We emphasize the importance of proper preanaestheticevaluation, intellectual, mental and logistical preparation which should be done before anaesthetising these types of patients.


Introduction
Osteogenesis imperfecta(OI), also known as brittle bone disease, is a genetic disorder of connective tissue characterized by bones that fracture easily, often with little or no trauma. Osteogenesis imperfecta is caused by a faulty gene that instruct to make too little or poor quality of type 1 collagen 1 . The prevalence of osteogenesis imperfecta ranges from 1:60000 to 1:20000 2 depending upon type of OI. Inheritance in nearly allcases follows an autosomaldominance pattern, although sporadic cases are common. The disorder is frequently associated with blue sclera, dental abnormalities 3 (dentinogenesisimperfecta), progressive hearing loss, and a positive family history. The most common classification for OI was developed by Sillence 4 .
Anaesthetic implication of OI includes difficult intubation 5 ,platelet dysfunction,cardiovascular abnormalities like mitral valve prolapse 6,7 , tendency to develop malignant hyperthermia 8,9 and problems with positioning of patient due to brittle bones.

Case report
A 54-year-old male patient presented in emergency room with acute retention of urine. He was a known case of OI tarda (Fig 1). Immediately foley's catheterization (no.-16fr.) was done to relieve retention. X-Ray KUB of the patient revealed a right side renalcalculus and a vesicle calculus and was planned forcystolithotomy(Fig2). surgery, his vitals remained stable and no rescue medication was required. Operation lasted for about 40 min and patient had an uneventful recovery. He was discharged on 5 th postoperative day.

Discussion
Osteogenesis imperfecta is a rare autosomal dominant inherited disease of connective tissues that affects bones, sclera and inner ear 10 . The incidence is higher in females. Clinically, it occurs in twoforms: osteogenesis imperfecta congenita and osteogenic imperfecta tarda. With congenital forms fractures occurin uteroand death is usuallyin perinatalperiod. The tarda form typically manifestsduringchildhood or early adolescence, but the patients have a normal lifespan.
Management of anaesthesia is influenced by coexisting orthopaedic deformities 11 ,vulnerabilities to fracture during perioperative period, associated cardiac abnormities, impaired platelet function, tendency to develop hyperthermia and rarely extra skeletal manifestations 12 . Due to abnormal skeletal growth difficult airway must always be anticipated in such patients. Associated kyphoscoliosisalong withpectus carinatum may decreasevital capacity, chest wallcompliance with resultingarterial hypoxemia due to ventilation perfusion mismatch and this can leadto increased risk under GA. Succinylcholine should be avoided as fasciculation can lead to fractures. Regional anaesthesia is acceptable in selected patients as it avoids need for tracheal intubation but may be difficult because of kyphoscoliosis. Before giving regional anaesthesia, coagulation profile must be screened due to associated increase in bleedingtime despite normalplatelet count 13 .
For monitoring of blood pressure, automated blood pressure cuffs may be hazardous as over inflation may result in fracture. Duringprolonged surgery, all pressure points should be well padded and positioning ofpatient alongwith transportation 14 should be very gentle to prevent occurrence of fracture.
There have been several successful case reports of conductance of surgeryunder generalanaesthesia in On preanaestheticevaluation, thepatient weighed 22 kg, length 94 cm, head circumference 50cm, chest circumference 65 cm, and was bedridden. He had undergone previously cystolithotomy at 6 months of age (details of that operation were not available). History revealed uneventfulantenatal period and no delay in milestones. Patient developed normally upto 10yr of age and after that he started having skeletal fractures. There wasno positive family history.
The patient was accepted for surgery as ASA grade II. In view of anticipated difficult airway, it was planned to conduct the case under regional anaesthesia. In the operation theatre, i.v. line was secured using 18 G cannula. Monitoringincluded 5leadECG, manual blood pressure monitoring, SpO2, EtCO2, and temperature. Difficult airway cart was also kept standby. After preloadingwith 500mlofRinger lactatei.v., caudal epidural anaesthesia was given in lateral position with 14mlof 0.25% of bupivacaine. Midazolam 1.0mg and butorphanol1.0 mgi.v. was given for sedation. During patients with osteogenesis imperfecta. Karabiyik et al 1 have recommended TIVAalongwith ILMAto manage elective case, while Malde et al 14 have successfullyused balanced generalanaesthesia in a case of osteogenesis imperfecta with gross deformity of pelvis for abdominal hysterectomy.
In ourpatient, we avoided generalanaesthesia due to anticipated difficult airway(attributed tolimited mobility of cervical spine, short neck and absent dentition), restrictive lung disease (due to associated kyphoscliosis, pectus carinatum) and susceptibility to malignant hyperthermia. However, preparation was kept ready in operation theatre for managing difficult airway in case of emergency. We preferred regional anaesthesia since the patient had to undergo a lower abdominal surgery and to avoid risk related to general anaesthesia. Before giving regional anaesthesia a thorough preoperative workup of patient was done with special attention to coagulation profile as these patients are prone to have abnormalbleeding tendencies. Patient's BT, CT and PT were within normal limits. Caudal epidural was chosen as preferred anaesthesia technique over spinal anaesthesiaas itwas difficult to perform lumbar puncturedue to associated kyphoscoliosis and unpredictability of the level of block. The effect of caudal block was till T10 leveland course of surgery was uneventful.
To summarise, patients with OI pose a significant challenge to anaesthesiologistowingto difficult airway ,problems with positioning,fractures, tendency for hyperthermia and platelet functionalabnormalities. Only thorough preoperative workup and prompt management can improve the outcome in these patients.